1. Technical Field of the Invention
The present invention relates to packet switching streams of communication traffic onto a common transport network and, in particular, to the dispersion of correlated bursts within packet switched streams of communications traffic.
2. Description of Related Art
Reference is now made to FIG. 1 wherein there is shown a block diagram of a prior art packet switched access communications system 10. It is well known in the art to operate a communications system 10 wherein the streams of communications traffic 12 output from a number of sources 14 and carried by a corresponding number of independent communications links 16 are added together by a packet switched access node 18 into a single packet switched stream of communications traffic 20 carried by a common transport (link) network 22. The conventional data communication system is one example of just such a communications system 10 wherein multiple subscriber voice communications (each comprising a stream of digitized traffic) are added together onto a shared media communications link.
Multimedia traffic (such as internet (data) or video transmission) exhibits a bursty transmission character. By this it is meant that the information being conveyed by the individual streams of communications traffic 12 flows in short bursts 24 with silent, sometimes relatively long, intervals 26 therebetween. Each burst 24 is comprised of at least one frame (not shown) of data. It has been discovered that in instances where several streams of bursty communications traffic 12 are added by node 18 onto a common transport network 22, the bursts 24 in the individual streams may, when the same traffic types are combined, correlate with each other in the output packet switched stream of communications traffic 20. Thus, the individual bursts 24 add into cumulative bursts 28. If the cumulative burst approaches or exceeds the transmission capacity of the common transport network 22, instances of network congestion may arise. There is a need then for a mechanism to break down or disperse the correlation between individual bursts 24 in added streams of bursty communications traffic 12.